Refacing tool for valve seats



May 19, 1936. L, Q BEARD 2,041,587

REFAQING TOOL' FOR VALVE SEATS Filed July 29, 1952 Patented May 19, 1936 UNITED STATES REFACING TOOL FOR VALVE SEATS Lawrence 0. Beard, Lancaster, Pa.

Application July 29, 1932, Serial No. 625,916

1 Claim.

This invention relates to improvements in refacing tools and more particularly to tools for refacing worn or imperfect valve seats of internal combustion engines.

The principal object of the invention is to provide means for securing the cutter blades in the cutter head whereby danger of breaking the relatively hard blades which must be employed is reduced to a minimum.

Other objects and advantages of the invention will be in part described and in part apparent as the specification is read in connection with the accompanying drawing, in which:

Figure 1 is a perspective view of the tool partly in section;

Figure 2 is a bottom plan view of the tool shown in Figure 1;

Figures 3 to 9 inclusive show the various parts of the tool disassembled. Thus Figure 3 is a perspective view partly in section of the operating or handle member; Figure 4 is a section through the blade retaining and clamping cutter head cap; Figure 5 is a section through the cutter head; Figures 6 and 7 sectional views of the 25 blade clamping washer and nut respectively and Figure 8 a perspective of the pilot stem.

Referring more specifically to the drawing l denotes a preferably cast iron cutter head of substantially inverted cone shape and having flat upper .and lower faces 2 and 3 respectively. Narrow ring like portion 4 extends between the top of conical face 5 of the cutter head to the upper flat surface 2 thereof, just referred to. The cutter head is formed with a plurality of open 35 ended, inclined slots 6 adapted to snugly but slidably receive therein the cutter blades 1. These slots, which are of uniform depth, extend through the lower flat surface 3 and .at their upper ends open through ring like portion 4 slightly below 40 the fiat top surface 2. These slots are of uniform depth and the bottom walls I2 thereof substantially parallel the cone face 5, and extend at an angle of approximately forty-five degrees to the aforesaid upper and lower faces 2 and 3. 45 The blades 1 are substantially rectangular in cross section except at their ends. Thus the lower end of each blade is formed with the two converging inner and outer angular faces 8 and 9 respectively, while the upper end is cut on an angle to the longitudinal axis of the cutter blade, as at It). The length of blades 1 is such that when inserted in the slots 6 the upper angular end or face ll] of the blades will be substantially bisected by a peripheral line drawn approximate- 65 ly midway the top and bottom extremities of the ring like portion 4 of the cutter head, and the respective lower end faces 8 and 9 will be flush with the flat surface 3 of the cutter head and the wall of bore ll extending axially through said cutter head. Blades 1, when seated in the inclined slots 6 are in tilted relation with respect to the side wall of the cutter head.

A top plate or cap l2 of relatively stiff sheet steel seating upon the top surface 2 of the cutter head is formed with a depending peripheral flange I3 which snugly engages the peripheral ring like portion 4. The lower edge of this flange terminates approximately mid-way the depth or top and bottom extremities of ring like portion 4 and engages the angular upper ends ID of the blades 1 midway the top and bottom edges thereof, thus securely and non-resiliently clamping the blades in place. The cap I2 is provided with a central opening I4 axially alined with opening H for accommodating the lower reduced threaded end I5 of a handle member Hi, the upper end of which handle member is formed with wrench engaging faces I1 and a hand grip I8 respectively. When the handle member is inserted in openings l4 and II the shoulder l9 engages the cap l2 and holds the cap in place. A ring like nut 20 is then screwed upon the threaded end l5 of the handle member I6 against the lower ends of the cutting blades, thus forcing the cap to its seat and also tightly clamping the blades between the cap and the ring nut. In order to prevent the nut 20 from shearing off or otherwise damaging the hard and brittle cutter blades, a metal washer 2| is preferably employed. This washer engages the inclined faces 8 of the blades midway their length and thus the nut can be screwed home with considerable force without danger of breaking or chipping. As the upper end In of the cutter blades is inclined at an angle greater than a right angle to the flange I3 of cap I2, it is unnecessary to notch the blades in order to insure proper contact between these parts. Heretofore a great proportion of blade breakage has been due to notching the blades and/or the fact that the bearing point or contact of the flange of the cutter head top plate or cap was close, too close to the top or bottom edge of the blades.

The lower end, of handle member 16 is formed with a threaded bore 22 to receive the reduced threaded end 23 of a pilot stem 24 for guiding the tool into the valve seat to be ground. In use the tool is rotated either by means of the hand grip [8, or by applying a standard wrench to the squared end I! of the handle member.

While I have shown the cutter as being provided with seven blades, it is of course understood that the number of blades may be increased or decreased as desired.

Having thus described my invention,

What I claim is:

A valve seat refacing tool comprising a cone shaped centrally bored cutter head having inclined grooves of uniform depth therein, blades having inclined upper ends seated in said grooves, a perforated flanged top plate seated upon the top surface of said cutter head, said plate having its circumferential flange downwardly extended and snugly engaging the upper portion of said cutter head, and the lower edge thereof engaged with the inclined upper ends of said blades, a member having its externally threaded lower end extending downwardly through the bore of the cutter head and having a shoulder seated upon said plate for clamping the flange of said plate to the upper ends of said blades, and a nut and washer threadedly connected with the lower end of said member for rigidly supporting the lower ends of said blades, the diameter of said washer being equal to the diameter of the lower surface of said cutter head to support said blades at a point midway their width, said shouldered member extending upwardly to provide a rotating handle and torque transmitting element, the low- 'er end of said member having an internally threaded bore, a pilot stem inserted in said bore,

said stem engaging said nut for locking said nut 15 in its clamping position.

LAWRENCE O. BEARD. 

